下一个fallacy是：
Fallacy: Computers at low utilization use little power.
从经济学的角度来说，就是任何物理的基建设施，都有一个固定的日常投入，而且随着产出的增加，边际投入曲线也是“曲线” —— 所以投入产出并不是线性关系。作者举例：
Even given 5 years to learn how to run the SPECpower benchmark well, the specially configured computer with the best results in 2012 still uses 33% of the peak power at 10% of the load. Systems in the field that are not configured for the SPECpower benchmark are surely worse.
第三个fallacy是：
Fallacy: Designing for performance and designing for energy efficiency are unrelated goals.
也就是说，两者实际上是相关的，原因在于：
Since energy is power over time...
第四个fallacy是：
Pitfall: Using a subset of the performance equation as a performance metric.
这是在说，不能以偏概全，用作者的话来说：
We have already warned about the danger of predicting performance based on simply one of the clock rate, instruction count, or CPI. Another common mistake is to use only two of the three factors to compare performance.
其中一个指标就是MIPS (million instructions per second)：
million instructions per second (MIPS) A measurement of program execution speed based on the number of millions of instructions. MIPS is computed as the instruction count divided by the product of the execution time and 10^6.
公式就是：
而如果联系clock rate和CPI，MIPS公式可以改写为：
可以看出这不是一个很好的衡量指标。问题在于：
First, MIPS specifies the instruction execution rate but does not take into account the capabilities of the instructions.
Second, MIPS varies between programs on the same computer; thus, a computer cannot have a single MIPS rating.
Finally, and most importantly, if a new program executes more instructions but each instruction is faster, MIPS can vary independently from performance!
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